Core daylight illumination apparatus systems for buildings are intended to collect, concentrate and direct sunlight from the exterior of the building to internal workspaces for the purposes of replacing a portion of the normally required electrically powered lighting and of improving lighting quality within those workspaces. Widespread use of such systems in commercial workspaces could significantly reduce energy consumption and greenhouse gas emissions. To foster widespread usage, the building core daylight illumination systems must be cost effective, robust, and compatible with common commercial building design and construction practices.
Previous work on building daylight illumination has not been successful for a number of reasons. Passive daylighting efforts including skylights, vertical light pipes, and other methods of directing non-concentrated or untracked sunlight fail to meet commercial illumination standards over a practical area or during a reasonable percentage of the year and do not provide significant power savings. European Patent application no. 1174658, entitled “Light Carrier System for Natural Light”, by Guzzini, discloses a basic apparatus which collects lights and passes it to the interior of the building through a diffuser. U.S. Pat. No. 6,299,317, “Method and apparatus for a passive solar day lighting apparatus system” by Ravi Gorthala has a Fresnel component, but a “passive” system of light transportation into the building. The collected light would not, therefore, be expected to travel efficiently any distance once inside the building envelope. Control of light distribution is also problematic due to the wide range of angles of light entering the building.
Previous active daylighting, herein referred to as “sunlighting”, efforts also have significant limitations that affect system cost or life cycle. Designs that include an optical fiber mounted such that it moves with the tracking optics are limited by the resistance caused by the bulky array of moving fiber. Accurate tracking in those cases is costly to provide. One such patent is U.S. Pat. No. 7,295,372 to Parans Daylight discloses a system involving a convex and concave lens to focus sunlight onto transmitting fibers. U.S. Pat. No. 7,813,061, also to Parans Daylight, discloses light focusing lenses which are mobile via ball joints and mobile frames that move independently to change the direction of the lenses. The light collecting element and optical fibers receiving the collected light must also move with the apparatus, which creates problems in keeping the light collecting element aligned to collect sunlight efficiently, and leads to lost light as the optical fiber flexes.
Generally, designs that utilize long optical fibers from the collector to the lighting fixture are further limited by the properties of the optical fiber over long distances, which distances cause significant light losses due to bulk absorption and noticeable color spectrum shifts.
Although there are several patents and patent publications pertaining to the concept of concentrating sunlight, or suggesting moving to track the sun, no solutions are offered for a whole apparatus system to make sunlight illumination work in a real context. U.S. Pat. No. 5,169,456 discloses the mechanical aspect of a weather protected “two-axis solar collector mechanism”. No contemplation is made of the necessary optical components of this mechanism, apart from the prediction that a Fresnel lens could be used.
Externally mounted lighting systems have been provided in Vancouver, Canada, using adaptive butterfly arrays of mirrors (United States Patent Publication 20100254010 and U.S. Pat. No. 8,000,014) and parabolic mirrors. Such systems have been able to deliver adequate luminous flux to the interior of the buildings they serve, but the physical aspects of these building “add-ons” are considerable, as they project up to four feet from the buildings' original exterior wall.
The extrinsic materials described herein (European Patent Application No. 1174659, U.S. Pat. Nos. 6,299,317, 7,295,372, 7,813,061, 5,169,456 and 8,000,014, and United States Patent Application Publication 20100254010) and U.S. Provisional Application Ser. No. 61/541,305 are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
The related art discloses solutions that have cost and performance issues related to relying on optical fiber to transport light over long distances, requiring high tracking accuracy required to minimize fiber diameter, and having reduced tracking mechanism accuracy limitations when needing to flex fiber. Thus, an improved manifestation of a building core sunlight illumination apparatus system that is more effective in terms of total cost per delivered lumen-hour, quality of delivered light, life cycle and suitability to inclusion in new commercial building construction or renovation is needed.
Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints, and open-ended ranges should be interpreted to include commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary.